Floor polisher



y 1954 E. o. KOHL 2,683,884

FLOOR POLISHER Filed May 7, 19491 5 Sheets-Sheet l INVENTOR. Erhard Q[fa/ll ATTOHNE Y.

1954 E. o. KOHL 7 4 FLOOR POLISHER Filed May 7, 1949 3 Sheets-Sheet 3Fig.3

y INVENTOR.

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Patented July 20, 1954 FLOOR POLISHER Erhard O. Kohl, Massillon, Ohio,assignor to The Hoover Company, North Canton, Ohio, a corporation ofOhio Application May 7, 1949, Serial No. 91,980

2 Claims.

This invention relates to floor polishers and more particularly to adual brush polisher in which the brushes rotate in opposite directions.

The present invention is particularly concerned with the arrangement ofthe various parts of the complete assembly in order to provide apolisher having a very low center of gravity to give greater stabilityand ease of operation.

In polishers of the oppositely rotating brush type it is usual to drivethe vertically extending brush shafts by worm gears on opposite ends ofthe shaft of a horizontally positioned motor. In the usual constructionthis positions the center of gravity of the assembly as a whole to oneor the other side of a line connecting the center lines of the brushshafts which renders the polisher unstable in operation regardless ofwhere the handle is attached.

Also when conventional motors, having the motors stator evenlydistributed about the shaft axis, are used to drive the brushes thecenter of gravity of the entire assembly is so high that it furthercontributes to the unstability of the polisher in use.

According to one aspect of the present invention a unicoil motor is usedwith the major portion of the weight of the field located toward a lineconnecting the center lines of the brushes and away from the motor shaftaxis so that the center of gravity of the entire assembly is locatednearer to a line connecting the center lines of the brushes. The use ofa unicoil motor also renders it possible to lower the concentratedweight of the stator downwardly so as to materially lower the center ofgravity of the entire assembly.

Both of the foregoing features contribute materially to the stability ofthe polisher in use.

In order to further stabilize the action of the polisher of thisinvention in operation, the manipulating handle is pivoted to the mainframe on the center line of the brushes and slightly below the center ofgravity in the entire assembly so that the center of gravity of theassembly is positioned above and to the rear of the axis upon which thepropelling handle is pivoted.

According to another aspect of the present invention a main casting isprovided which forms a support for all of the working parts of thepolisher including the propelling handle, the motor stator, the bearingsfor the motor rotor, the motor brushes, the headlight for illuminatingthe surface being polished, and the bearings for the brush shafts aswell as gear housings for enclosing the worm gearing between the motorshaft and the brush shafts.

The main casting is made in two parts divided vertically midway betweenthe axis of the brush shafts. The one part has locating means thereonfor locating the laminations of the motor stator which may be boltedthereto as a semipermanent assembly whereby the motor rotor may bedisassembled independently of the stator for purposes of repair, etc. bymerely separating the two parts of the main casting.

According to another feature of this invention the main casting hasfalls extending upwardly therefrom which cooperate with downwardlyextending ribs on the appearance housing to form a cooling air circuitwhereby cooling air is drawn inwardly through louvers in the appearancehousing by the cooling air fan, passes between the motor rotor andstator to keep the motor cool, passes upwardly through the fan chamberthrough a passage to a chamber housin the headlight, and is dischargedthrough an opening in the appearance housing through which the lightrays are projected.

Also, according to this invention, the cooperating ribs on the mainframe and on the appearance housing form the fan chamber for the coolingair fan.

Other objects and advantages of this invention will become apparent asthe description proceeds when taken in connection with the accompanyingdrawings in which:

Figure 1 is a perspective view of the polisher of this invention showingthe arrangement of the parts and with the appearance housing raisedupwardly to depict how it cooperates with the main casting to form thecooling air circuit;

Figure 2 is a plan view looking downwardly on the polisher of Fig. 1 andfurther showing the arrangement of parts; and

Figure 3 is a cross-sectional view taken on line 3-3 of Fig. 2 andlooking in the direction of the arrows.

Referring to the drawings, the reference numeral [0 generally representsthe main frame preferably formed of an aluminum casting and formed intwo parts I I and I2 divided on a vertical plane I3 substantially midwaybetween the axis of the brush shafts. The two parts are machined ontheir dividing plane and are detachably secured together, preferably bymeans of bolts I4.

Formed integrally with the main frame parts II and I2 are upwardlyextending gear housings I5 and I6. Each of the housings I5 and I6 isbored to receive a hearing I! for the vertically extending shafts I8which rotatably support a pair of opposite rotating polishing brushes 9and 20 which are secured to the lower ends of the shafts IS in anysuitable manner.

Keyed to the upper ends of each of the shafts I8 is a worm gear 2| whichmeshes with worms 22 formed on the opposite ends of a motor shaft 23.

The worms 22 and the gears 2| are so formed that rotation of the shaft23 will rotate the brushes l9 and 26 in opposite directions.

The gear housings l5 and I6 also include integral supports for thebearings for the shaft 23 as indicated at 25 and 26 and are providedwith closure plates 21 and 26 to retain a suitable lubricant within thehousings.

The shaft 23 carries the motor rotor comprising the iron laminations 29,winding 30, and the commutator 3|. The part |2 of the main frame alsoincludes an integral upwardly extending protuberance 32 having asubstantially circular undercut flange 33 for receiving the fieldlaminations 34. The field laminations 34 are semipermanently securedwithin the circular flange 33 by bolts 35. The outer surfaces of thepole pieces 36 of the lamination 34 are in the form of a segment of acircle whereby the circular flange 33 will properly position the poles36 relative to the rotor laminations 29.

As shown in Fig. l the yoke 31 of the laminations 34 is extendedforwardly and across a line connecting the center lines of the brushshafts I8. A single field coil 38 surrounds the yoke 31 of the fieldlaminations 34 to provide the necessary motive power.

The main casting It being of aluminum and the parts of the motor beingiron and copper, it is obvious that a large proportion of the weight isconcentrated in the motor. By making the motor of the unicoil type andextending its yoke across a line connecting the center lines of thebrush shafts it is obvious that the center of gravity of the entireassembly will be shifted towards the axes of the brushes.

It is also obvious that by the use of a unicoil motor the concentratedweight of the motor will be lowered in relation to the other parts.

The right hand half l2 of the main frame also has integral supports 40having aligned bores for receiving the motor brush holders 4| toproperly position the motor brushes 42 relative to the commutator 3|.

. The main frame l also includes integral protuberances 45 forsupporting the pintles 46 for the propelling handle bail 41. As shown,the pintles 46 .are positioned on a line connecting the center lines ofthe brush shafts [8, below the center of gravity of the assembly as awhole so that the center of gravity of the assembly is positionedupwardly and rearwardly of the axis of the pintles.

Integral with the half ll of the main casting and extending upwardlytherefrom is a rib 50 which, as will presently appear, forms a portionof the enclosing casing for a cooling fan suitably secured to the motorshaft. Secured, in any suitable manner, to the half H on the main frameand extending parallel to the rib 56 is a plate 52 having an opening 53forming the eye for the fan 5| as clearly shown in Fig. 3.

It is to be noted that the plate 52 stops short of the forward end ofthe rib 50 and that the rib 56 includes a right angled extension 54which interfits with the rear edge of the plate 52 to close off the rearend of the fan housing.

Extending at right angles from the forward end of the plate 52 is anupwardly extending reflective plate 55 which is secured to the mainframe II! in any suitable manner. Secured to the base of plate 55forwardly thereof is an electric socket 56 for supporting a headlight 51in front of the reflective surface of the plate 55.

A dome-shaped streamlined appearance housing generally indicated by thereference numeral 66 fits over the top of the main frame ID so as tohide the working parts of the polisher. The lower edge 6| of the housing66 fits about the periphery of the main frame If! and is normallysecured thereto in any suitable manner.

The housing 66 is preferably made of a thermosetting type of phenolicplastic. Extending downwardly from the dome of the housing 66 areintegral ribs 52, 63, and 64. The ribs 62 and 63 cooperate with the rib50 of the main frame and the plate 52 to complete the fan housing andalso the forwardly extending passage 65 leading to the headlightchamber. The rib 64 cooperates with the plate 55 and with the sides ofthe housing to form a motor chamber on its rear side and a headlightchamber on its forward side.

The dome of the housing 60 is provided with louvers 66 (Fig. 3) toprovide for the entrance of cooling air and the front side wall thereofis provided with an opening 61 which serves the dual function ofproviding an exit opening for the cooling air and an opening throughwhich light rays are projected from the light 51 onto the surface beingpolished.

The handle bail 41 is of channel shape as shown and one leg thereofforms a housing for a conductor cord 68 leading from a switch in thehandle (not shown) and being electrically connected to the motor and thelight 51 in any suitable manner. The housing 60 is provided with anopening 69 (Fig. 3) adjacent one of the pintles 46 to provide for theentrance of the cord 68 into the motor chamber. As shown in Fig. 1 anupwardly extending rib 16 on the main frame |0 interfits with thehousing 60 to close off the motor chamber from the headlight chamber andprevent recirculation of cooling air. The rib 16 is provided with asuitable notch to receive the conductor cords leading to the headlight51.

The opening 69 is made large enough to provide for pivotal movement ofthe bail 41 about the pintles 46 without interfering with the cord 63.Any suitable latch mechanism may be provided for holding the handle inits vertical storage position when not in use. A furniture guard of anysuitable character may encircle the periphery of the main frame l0.

During the operation the motor rotates the brushes l9 and 20 in oppositedirections and rotates the cooling fan 5|. Cooling air is drawn into themotor chamber through the louvers 66, passes through the eye 53 of thefan, is discharged upwardly and forwardly through the channel 65, formedby the coacting ribs on the main frame it and the housing 66, passesinto the light chamber and exits by the opening 61.

The coacting ribs on the main frame and housing prevents therecirculation of cooling air and insures that it passes over both themotor and the headlight to cool them.

If it is desired to remove the motor rotor for repair or replacement itis unnecessary to disturb the assembly of the motor stator with theframe. The bail 41 is removed by removing the pintles 46, housing 60raised upwardly, and the two halves and I2 of the main frame separatedby removing the connecting bolts. Thereafter the motor rotor can be slidhorizontally out of the stator.

From the foregoing it can be seen that this invention provides a floorpolisher having a compact arrangement of parts utilizing a unicoil motorwhereby the center of gravity of the unit is shifted forwardly anddownwardly to give greater stability, in which all of the parts aresupported from the main frame in such a manner that the motor rotor canbe disassembled from the stator Without disturbing the assembly of themotor stator with the frame and in which the appearance housing and mainframe cooperate to form cooling air ducts for leading cooling air overboth the motor and the headlight.

While I have shown and described but a single embodiment of my inventionit is to be understood that this embodiment is to be taken asillustrative only and not in a limiting sense. I do not wish to belimited to the specific structure shown and described but to include allequivalent variations thereof except as limited by the scope of theclaims.

I claim:

1. In a floor polisher, a main frame, a pair of spaced vertical axisshafts rotatably carried by said frame, a shaft rotatably supported bysaid main frame on a horizontal axis to the rear of a line connectingthe axes of said vertical axis shafts, gearing drivingly connecting theends of said horizontal axis shaft with the upper ends of said verticalaxis shafts to drive them in opposite directions upon rotation of saidhorizontal axis shaft, a motor rotor carried by said horizontal axisshaft for rotating it, and a U-shaped unicoil motor stator carried bysaid frame with its pole pieces embracing said rotor and its yoke and.coil extending across the line connecting the axes of said vertical axisshafts whereby the center of gravity of the polisher lies between theaxis of the horizontal axis shaft and the line connecting the axes ofsaid vertical axis shafts.

2. In a floor polisher according to claim 1 including a manipulatinghandle pivoted to said main frame on an axis passing through the axes ofsaid vertical axis shafts and lying below the center of gravity of theassembly whereby the center of gravity of said assembly lies above andto the rear of the pivotal axis of said handle.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,622,166 Schultz Mar. 22, 1927 1,820,482 Orth Aug. 25, 19311,854,638 Woods Apr. 19, 1932 1,877,951 Norris Sept. 20, 1932 1,927,225Woods Sept. 19, 1933 1,927,227 Woods Sept. 19, 1933 1,928,246 BrinkerSept. 26, 1933 1,937,287 McGee Nov. 28, 1933 2,119,386 Holm-Hansen May31, 1938 2,258,165 Sassano Oct. 7, 1941 2,300,138 Steele Oct. 27, 19422,340,379 Hahn Feb. 1, 1944

